GTK - TDC analysis

Lukas Perktold

14th April 2010

Progress

► Move to new Design Kit version 1.6.0.3

Library based -> many issues

► GDS2 based

► Match Measurements to Simulation

Document Errors

Propose Solutions

DK 1.6 – Library BasedIssues

• Copy library and attach it to the new DK version

Problems:

1. Missing functions in some PCells (Parameterized Cells)

2. Twelve new DRC Errors (Design Rule Check): -> most of them introduced by modified Layouts

3. LVS mismatch (Layout Versus Schematic)

Possible Solutions:

1. Flatten problematic Pcells

2. Flatten problematic Pcells

3. Change Layout

+ exact copy of design (including PCells, Vias, hierarchy)- compatibility problems ( depends on design )

DK 1.6 – Library BasedDRC issues

• Different Layout for same cell and parameters

DK 1.6 – Library BasedLVS issues

Special Problem:

Assura doesn’t extract subc contact in new DK

No LVS match

DK 1.6 – GDS2 basedIssues

• Copy schematics• Export and ReImport Layout

Problems:

1. (Only) Two new DRC errors

2. LVS [Assura (VLDB)] - EndOfColumn – problems with malformed devices

3. LVS [Assura (VLDB)] - TOP Level - exits with error: unbound devices

4. LVS [Assura (CDL)] - TOP Level - error generating CDL netlist

Possible Solutions:

1. Needs to be investigated

2. Replace problematic devices

3. Not investigated - Use LVS [Assurra (CDL)]

4. Needs more investigations – problem with ESD devices + CDL parameters

+ less compatibility problems - complete flat layout ( no PCells / no vias / etc.); but hierarchy is conserved

CDF Parameter Issues

• Component Description Format+ attached to each cell in library+ handles callback functions+ defines parameters of a cell+ provides section for simulation information (gets updated on creation of a symbol view)+ …

• Inconsistent data in some libraries(not introduces by DK v. 1.6)

+ cause ‘wrong’ simulation results+ introduce errors in CDL netlisting

SolveCDF Parameter Issues

Instance Level(Important for simulation)

Base Level(Important for CDL netlisting)

Watch log window

Edit Simulation Information

Summary

• Library Flow – problems with updated Layout for some devices (introduce new DRC errors)

• GDS2 Flow – problems with old Layout (LVS has problems to extract devices with old Layout)

• The move from DK v. 1.4 to DK v. 1.6 is MUCH more problematic as expected

• No QRC possible on TOP Level without effort• Up to EndOfColumn running DRC, LVS (VLDB +

CDL) and corrected CDF data

• complete move (wish: be able to run QRC on TOP Level)

• match simulation to measurements (corner simulation)

• List all errors found through measurements

• check if the all errors can be explained

- Weak performance (e.g. INL) of the TDC for rising edges - Zero dies out for higher frequencies - compare RFN settling values - ...

• write documentation

• propose solution to errors found

Outline